205542817 has 4 divisors (see below), whose sum is σ = 216360880. Its totient is φ = 194724756.

The previous prime is 205542811. The next prime is 205542847. The reversal of 205542817 is 718245502.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 205542817 - 2³ = 205542809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205542811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5409003 + ... + 5409040.

It is an arithmetic number, because the mean of its divisors is an integer number (54090220).

Almost surely, 2^205542817 is an apocalyptic number.

It is an amenable number.

205542817 is a deficient number, since it is larger than the sum of its proper divisors (10818063).

205542817 is a wasteful number, since it uses less digits than its factorization.

205542817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10818062.

The product of its (nonzero) digits is 22400, while the sum is 34.

The square root of 205542817 is about 14336.7645234202. The cubic root of 205542817 is about 590.1568260692.

The spelling of 205542817 in words is "two hundred five million, five hundred forty-two thousand, eight hundred seventeen".